I've dived both the Salem Express and the Leopoldsville.
I must have dived the Salem Express relatively soon after the disaster. Didn't know the history when i entered the water, but found it a very uncomfortable dive. Found out about its history once back on the deck and was very unhappy they choose her as a site. I'm not sure that I would want to dive it again.
The Leopoldville I've dived a few times. The first dive was awful, we had all sorts of issues, my buddy and I got caught in line. The shot was dragged down, huge tide, very dark, poor vis', the whole group found it quite scary. With the lose of the shot we ended drifting across the entrance to Cherbourg harbour, not a good thing to do.
I've dived her a few times since, mostly an excellent dive, I've never forgotten the first and always treat the site with a huge amount of respect. She is truly magnificent, especially in good vis'.
It is some times very easy to forget the tragedies surrounding the majority of ship wrecks, especially with the passing of time.